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C E Fuenzalida

Publications and source records attributed to C E Fuenzalida.

6 recordsLinked to original sources
PubMed1994

Predictors of successful radiofrequency ablation of extranodal slow pathways.

Catheter positioning for radiofrequency ablation of extranodal slow pathways is often guided by local electrogram recordings. To determine the predictors of successful ablation sites, we reviewed data from 32 successful and 104 unsuccessful sites. Univariate predictors of a successful site included the occurrence of junctional rhythm during ablation (P < 0.001), shorter time to onset of junctional rhythm (P = 0.05), the presence of a discrete slow pathway potential (P < 0.001), a smaller ratio of the amplitude of the atrial:ventricular electrogram (P = 0.04), later timing (P = 0.001) and longer duration (P < 0.001) of the atrial slow pathway electrogram, and the duration of (P < 0.001), and maximal voltage used during ablation (P < 0.001). By multivariate analysis junctional rhythm (P < 0.001), a discrete slow pathway potential (P = 0.003), a longer duration of the atrial slow pathway electrogram (P = 0.01) and the duration of ablation (P = 0.02) were predictors of success. Because ablations at unsuccessful sites were often aborted at 10-30 seconds, a separate analysis was performed using only the 41 unsuccessful sites where the duration of ablation was > or = 30 seconds. The results were nearly identical. Thus, the occurrence of junctional rhythm during ablation and the morphology and duration of the atrial slow pathway electrogram may serve as guides for slow pathway ablation site selection.

Adolescent↗
PubMed1994

Low dose disopyramide often fails to prevent neurogenic syncope during head-up tilt testing.

Low dose disopyramide has been used to prevent neurally-mediated syncope during head-up tilt testing but a correlation between blood levels and efficacy has not been described. We measured disopyramide levels in 15 patients with recurrent syncope and positive 70 degrees head-up tilt tests who underwent one or more repeat tests on the drug. There were 9 males and 6 females, age range 15-78 years. Fourteen of the 15 patients had structurally normal hearts. The daily disopyramide dose was 645 +/- 165 mg (mean +/- SD). Patients developed syncope during 9 tests and had no syncope during 12 tests. The mean disopyramide level in patients with positive tests was significantly lower than the level in patients with negative tests (2.4 +/- 0.15 mu/mL vs 3.2 +/- 0.22 mu/mL, P = 0.018). Six patients were tested twice on different disopyramide doses. Five of these six patients had syncope during head-up tilt testing on the lower dose and negative tests on the higher dose (disopyramide levels 2.2 +/- 0.17 mu/mL vs 3.2 +/- 0.17 mu/mL, P = 0.004). Thus, disopyramide is effective in preventing neurogenic syncope during head-up tilt testing, but higher blood levels are often necessary for efficacy. In a given patient, failure to respond to low dose disopyramide does not preclude success on higher doses.

Adolescent↗
PubMed1993

Influence of a third extrastimulus in defining effective drug therapy during serial electrophysiological testing.

Many electrophysiology laboratories use three extrastimuli in all patients with ventricular tachyarrhythmias during antiarrhythmic drug testing, regardless of the mode of arrhythmia induction in the baseline state. The purpose of this study was to compare this pacing protocol (full protocol) with a protocol in which three extrastimuli were only used during drug tests, if they were required in the baseline state for arrhythmia induction (limited protocol). There were 181 electrophysiology tests performed on 69 patients with ventricular tachyarrhythmias that were retrospectively analyzed. In all studies the full protocol was used, but the results of stimulation were also analyzed assuming the limited protocol had been used. In the baseline state, sustained ventricular tachyarrhythmias were reproducibly inducible with one or two extrastimuli in 38 (55%) patients. Of these patients, six (16%) achieved a drug efficacy prediction using the full protocol versus 15 (39%) patients using the limited protocol (P < 0.001). In all 69 patients, the drug response rate increased from 25% to 38% (P < 0.01) using the limited protocol.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Palpitations occur frequently following radiofrequency catheter ablation for supraventricular tachycardia, but do not predict pathway recurrence.

Radiofrequency ablation of extranodal pathways is an effective treatment for supraventricular tachycardia, but late recurrences of pathway conduction do occur. To determine if recurrence of palpitations following ablation predicts pathway recurrence, we interviewed 77 patients who were at least 4 weeks status-post successful ablation of an accessory pathway (43 overt, 11 concealed) or slow pathway (23) for AV nodal reentrant tachycardia. Palpitations were reported by 45 (58%) patients postablation, and 28 (36%) patients reported palpitations lasting > or = 10 seconds and/or felt their symptoms represented recurrent tachycardia (major palpitations). Repeat electrophysiological testing was performed 3 months postablation in 53 patients, including 34 patients with palpitations (22 with major symptoms). Eight (10%) patients had recurrent pathway conduction demonstrated on repeat testing: two had no symptoms prior to restudy and six had major symptoms. One patient had major symptoms, but was found to have inducible atrial tachycardia and not pathway recurrence on restudy. Thus, 15 (68%) of 22 patients with major symptoms who were restudied had no pathway recurrence or inducible arrhythmia to explain their symptoms. Of the 24 patients not restudied, none has had documented recurrent tachycardia or overt pathway conduction by electrocardiogram over a mean follow-up of 335 +/- 138 (range 132-616) days. Thus, palpitations, including palpitations reminiscent of preablation symptoms, are common following radiofrequency ablation and often do not predict pathway recurrence. Repeat electrophysiological testing is frequently required to document long-term success of radiofrequency ablation for supraventricular tachycardia in patients with recurrence of major symptoms.

Adult↗
PubMed1990

The immune response to short-term nutritional intervention in advanced chronic obstructive pulmonary disease.

Nine patients with advanced chronic obstructive pulmonary disease (COPD) and recent weight loss resulting in a state of mild malnutrition were entered into a refeeding program at a clinical research center. They were divided into two groups, one using a hospital diet and the other a hospital diet with supplementation. Both groups of patients gained significant weight. Refeeding and weight gain were associated with a significant increase in absolute lymphocyte count and with an increase in reactivity to skin test antigens after 21 days of refeeding. Few changes occurred in large numbers of additional serum measurements during the study period. These preliminary observations suggest that dietary and supplementary refeeding may improve the immune responses in patients with COPD.

Aged↗